Research Database
Displaying 61 - 80 of 83
It takes a few to tango: changing climate and fire regimes can cause regeneration failure of two subalpine conifers
Year: 2018
Environmental change is accelerating in the 21st century, but how multiple drivers may interact to alter forest resilience remains uncertain. In forests affected by large high-severity disturbances, tree regeneration is a resilience linchpin that shapes successional trajectories for decades. We modeled stands of two widespread western U.S. conifers, Douglas-fir (Pseudotsuga menziesii var. glauca), and lodgepole pine (Pinus contorta var. latifolia), in Yellowstone National Park (Wyoming, USA) to ask (1) What combinations of distance to seed source, fire return interval, and warming-drying…
Publication Type: Journal Article
Escaping social-ecological traps through tribal stewardship on national forest lands in the Pacific Northwest, United States of America
Year: 2018
Tribal communities in the Pacific Northwest of the United States of America (USA) have long-standing relationships to ancestral lands now managed by federal land management agencies. In recent decades, federal and state governments have increasingly recognized tribal rights to resources on public lands and to participate in their management. In support of a new planning initiative to promote sustainable land management, we reviewed scientific publications to examine relationships between tribal social-ecological systems and public lands in the region. We identified key ecocultural resources,…
Publication Type: Journal Article
Regional and local controls on historical fire regimes of dry forests and woodlands in the Rogue River Basin, Oregon, USA
Year: 2018
Fire regimes structure plant communities worldwide with regional and local factors, including anthropogenic fire management, influencing fire frequency and severity. Forests of the Rogue River Basin in Oregon, USA, are both productive and fire-prone due to ample winter precipitation and summer drought; yet management in this region is strongly influenced by forest practices that depend on fire exclusion. Regionally, climate change is increasing fire frequency, elevating the importance of understanding historically frequent-fire regimes. We use cross-dated fire-scars to characterize historical…
Publication Type: Journal Article
Drought, Tree Mortality, and Wildfire in Forests Adapted to Frequent Fire
Year: 2018
Massive tree mortality has occurred rapidly in frequent-fire-adapted forests of the Sierra Nevada, California. This mortality is a product of acute drought compounded by the long-established removal of a key ecosystem process: frequent, low- to moderate-intensity fire. The recent tree mortality has many implications for the future of these forests and the ecological goods and services they provide to society. Future wildfire hazard following this mortality can be generally characterized by decreased crown fire potential and increased surface fire intensity in the short to intermediate term.…
Publication Type: Journal Article
Returning Fire to the Land—Celebrating Traditional Knowledge and Fire
Year: 2017
North American tribes have traditional knowledge about fire effects on ecosystems, habitats, and resources. For millennia, tribes have used fire to promote valued resources. Sharing our collective understanding of fire, derived from traditional and western knowledge systems, can benefit landscapes and people. We organized two workshops to investigate how traditional and western knowledge can be used to enhance wildland fire and fuels management and research. We engaged tribal members, managers, and researchers to formulate solutions regarding the main topics identified as important to tribal…
Publication Type: Journal Article
Opportunities to utilize traditional phenological knowledge to support adaptive management of social-ecological systems vulnerable to changes in climate and fire regimes
Year: 2016
The field of adaptive management has been embraced by researchers and managers in the United States as an approach to improve natural resource stewardship in the face of uncertainty and complex environmental problems. Integrating multiple knowledge sources and feedback mechanisms is an important step in this approach. Our objective is to contribute to the limited literature that describes the benefits of better integrating indigenous knowledge (IK) with other sources of knowledge in making adaptive-management decisions. Specifically, we advocate the integration of traditional phenological…
Publication Type: Journal Article
Review of broad-scale drought monitoring of forests: Toward an integrated data mining approach
Year: 2016
Efforts to monitor the broad-scale impacts of drought on forests often come up short. Drought is a direct stressor of forests as well as a driver of secondary disturbance agents, making a full accounting of drought impacts challenging. General impacts can be inferred from moisture deficits quantified using precipitation and temperature measurements. However, derived meteorological indices may not meaningfully capture drought impacts because drought responses can differ substantially among species, sites and regions. Meteorology-based approaches also require the characterization of current…
Publication Type: Journal Article
Effects of Drought on Forests and Rangelands in the United States: A Comprehensive Science Synthesis
Year: 2016
This assessment provides input to the reauthorized National Integrated Drought Information System (NIDIS) and the National Climate Assessment (NCA), and it establishes the scientific foundation needed to manage for drought resilience and adaptation. Focal areas include drought characterization; drought impacts on forest processes and disturbances such as insect outbreaks and wildfire; and consequences for forest and rangeland values. Drought can be a severe natural disaster with substantial social and economic consequences. Drought becomes most obvious when large-scale changes are observed;…
Publication Type: Report
Wildfire, climate, and perceptions in Northeast Oregon
Year: 2016
Wildfire poses a rising threat in the western USA, fueled by synergies between historical fire suppression, changing land use, insects and disease, and shifts toward a drier, warmer climate. The rugged landscapes of northeast Oregon, with their historically forest- and resource-based economies, have been one of the areas affected. A 2011 survey found area residents highly concerned about fire and insect threats, but not about climate change. In 2014 we conducted a second survey that, to explore this apparent disconnect, included questions about past and future summertime (fire season)…
Publication Type: Journal Article
Does prescribed fire promote resistance to drought in low elevation forests of the Sierra Nevada, California, USA?
Year: 2016
Prescribed fire is a primary tool used to restore western forests following more than a century of fire exclusion, reducing fire hazard by removing dead and live fuels (small trees and shrubs). It is commonly assumed that the reduced forest density following prescribed fire also reduces competition for resources among the remaining trees, so that the remaining trees are more resistant (more likely to survive) in the face of additional stressors, such as drought. Yet this proposition remains largely untested, so that managers do not have the basic information to evaluate whether prescribed…
Publication Type: Journal Article
Models predict longer, deeper U.S. droughts
Year: 2015
Severe, decades-long "megadroughts" that hit the southwestern and midwestern United States over the past millennium may be just a preview of droughts to come in the next century as a result of climate change, new research suggests. According to a new analysis of 17 state-of-the-art climate models and reconstructions of historical drought based on 1000 years of tree-ring data, the regions are heading into a period of unprecedented dryness even if CO2 emissions are dramatically reduced. Under a "business-as-usual" emission scenario, there's an 80% likelihood that at least one decades-long…
Publication Type: Journal Article
Resprouting Chaparral Dies from Postfire Drought
Year: 2014
California’s chaparral plant community composition can change when fire is followed by intense drought. By measuring postfire population demography coupled with physiological measurements during a severe drought, Pratt et al. were the first to directly link resprout mortality to mechanisms of drought stress and show how chaparral may be affected in the future by the increased frequency of fires combined with drought.
Publication Type: Report
Traditional Ecological Knowledge: A Model for Modern Fire Management?
Year: 2014
For many thousands of years, aboriginal peoples worldwide used fire to manage landscapes. In NorthAmerica, the frequency and extent of fire (both human caused and natural) were much reduced afterEuropean colonization. Fire exclusion became the policy in the United States for most of the 20thcentury as the country became more settled and industrialized. Past fire exclusion has helped producelandscapes that are highly susceptible to uncharacteristically severe wildfire. An urgent challengefor land managers today is to reduce fire risk through several means, including prescribed burning,without…
Publication Type: Report
Correlations between components of the water balance and burned area reveal insights for predicting forest fire area in the southwest United States
Year: 2014
We related measurements of annual burned area in the southwest United States during 1984–2013 to records of climate variability. Within forests, annual burned area correlated at least as strongly with spring–summer vapour pressure deficit (VPD) as with 14 other drought-related metrics, including more complex metrics that explicitly represent fuel moisture. Particularly strong correlations with VPD arise partly because this term dictates the atmospheric moisture demand. Additionally, VPD responds to moisture supply, which is difficult to measure and model regionally due to complex…
Publication Type: Journal Article
Social science research on Indigenous wildfire management in the 21st century and future research needs
Year: 2014
This article reviews social science research on Indigenous wildfire management in Australia, Canada and the United States after the year 2000 and explores future research needs in the field. In these three countries, social science research exploring contemporary Indigenous wildfire management has been limited although there have been interesting findings about how Indigenous culture and knowledge influences fire management. Research with Indigenous communities may be limited not because of a lack of interest by social scientists, but rather by obstacles to doing research with Indigenous…
Publication Type: Journal Article
Prescribed fire in North America forests and woodlands: history, current practice, and challenges
Year: 2013
Whether ignited by lightning or by Native Americans, fire once shaped many North American ecosystems. Euro–American settlement and 20th-century fire suppression practices drastically altered historic fire regimes, leading to excessive fuel accumulation and uncharacteristically severe wildfires in some areas and diminished flammability resulting from shifts to more fire-sensitive forest species in others. Prescribed fire is a valuable tool for fuel management and ecosystem restoration, but the practice is fraught with controversy and uncertainty. Here, we summarize fire use in the forests and…
Publication Type: Journal Article
Climate change tipping points: A point of no return?
Year: 2013
Summer 2012 saw records fall for intensity of drought and number, size, and cost of wildfires in the Central and Western United States, and the climate forecast calls for more of the same in the near and distant future. When wildfire breaks out, emergency responders decide their immediate strategy based on past experience and quick judgment calls. But in the long term, land managers need to plan for a warmer climate on a time scale of decades, or even a century or more, to better reflect the life span of trees and forests. Studies supported by the Joint Fire Science Program (JFSP) are…
Publication Type: Report
The relationship of large fire occurrence with drought and fire danger indices in the western USA, 1984-2008: the role of temporal scale
Year: 2013
The relationship between large fire occurrence and drought has important implications for fire prediction under current and future climates. This study’s primary objective was to evaluate correlations between drought and fire-danger-rating indices representing short- and long-term drought, to determine which had the strongest relationships with large fire occurrence at the scale of the western United States during the years 1984–2008. We combined 4–8-km gridded drought and fire-danger-rating indices with information on fires greater than 404.7 ha (1000 acres). To account for differences in…
Publication Type: Journal Article
The leaf-area shrinkage effect can bias paleoclimate and ecology research
Year: 2012
Premise of the Study: Leaf area is a key trait that links plant form, function, and environment. Measures of leaf area can be biased because leaf area is often estimated from dried or fossilized specimens that have shrunk by an unknown amount. We tested the common assumption that this shrinkage is negligible. Methods: We measured shrinkage by comparing dry and fresh leaf area in 3401 leaves of 380 temperate and tropical species and used phylogenetic and trait-based approaches to determine predictors of this shrinkage. We also tested the effects of rehydration and simulated fossilization on…
Publication Type: Journal Article
Drought-Driven Disturbance History Characterizes a Southern Rocky Mountain Subalpine Forest
Year: 2012
The view that subalpine forest vegetation dynamics in western North America are "driven" by a particular disturbance type (i.e. fire) has shaped our understanding of their disturbance regimes. In the wake of a recent (1990s) landscape-extent spruce beetle (Dendroctonus rufipennis Kirby) outbreak in the southern Rocky Mountains, we re-examined the temporal continuity in disturbance types and interactions and the possible role of drought on their occurrence by reconstructing antecedent disturbances for 11 sites across the Markagunt Plateau, southern Utah, USA. Multiple consistent lines of…
Publication Type: Journal Article